With the development of science and technology, microbiological instruments are gradually replacing manual operations, especially in automated blood culture, automated bacterial identification, and drug sensitivity analysis, where breakthroughs have been achieved. However, at present, they cannot completely replace manual operations. Based on whether isolation and culture are required, they are divided into automated culture systems and non-culture systems.
Automated Culture Systems: Automated culture systems are further divided into two main categories according to their functions: automated blood culture detection and analysis systems and automated microbial identification and drug sensitivity analysis systems.
Automated Blood Culture Detection and Analysis Systems: Automated blood culture detection and analysis systems primarily detect the presence of microorganisms in blood samples. During the culture process, a computer detection and analysis system automatically scans culture bottles manufactured using special processes. Through continuous real-time qualitative monitoring over 24 hours, if changes occur in microbial growth and metabolism, the instrument automatically alarms to indicate the presence of pathogens.
Automated Microbial Identification and Drug Sensitivity Analysis Systems: Typically, after suspected bacteria are isolated from the sample through manual culture, manual identification and drug sensitivity testing of the microorganisms are required. This process is not only time-consuming and complex but also susceptible to many influencing factors. Automated microbial identification and drug sensitivity testing systems replace manual labor in automated detection and analysis. Microbial identification and drug sensitivity analysis are performed simultaneously. Based on the principles of digital bioinformatics identification, a unique identification system is formed. Simultaneously, automated drug sensitivity analysis is performed using disk diffusion or micro-broth dilution methods, maximizing time savings, reducing manual operations, improving work efficiency, and ensuring the accuracy of test results.
Non-culture systems refer to systems that do not require pathogen culture. They focus on the rapid and dynamic detection of specific biomarkers, cellular components, or metabolites in pathogenic microorganisms. They indirectly achieve rapid etiological diagnosis using biochemical, immunological, and molecular biological techniques. The primary instrument used is a rapid microbial analyzer.
Biomarker detection: By detecting biomarkers of bacterial infection, infection and non-infection can be differentiated, the severity of disease can be dynamically assessed, and the rational use of antimicrobial drugs can be guided. Key indicators include procalcitonin, C-reactive protein, and interleukins, which are typically detected using immunoassay methods.
Pathogen component detection: Patients with infectious diseases often experience high fever, primarily related to the components of the pathogen itself. Detection of the components of pathogens themselves aids in the diagnosis of bacterial or fungal infections. Biochemical or immunological methods are commonly used. For bacterial endotoxins, techniques such as gel electrophoresis, colorimetry, and chemiluminescence can be used; for 1,3-β-D-glucan in fungal cell walls, methods such as the Limulus Amebocyte Lysate (LAL) G factor assay, ELSA, and immunoturbidimetry can be used; and for galactomannan in fungal cell walls, methods such as latex agglutination, radioimmunoassay, and enzyme immunoassay can be used.
Molecular biological detection of nucleic acid components allows for the direct extraction of DNA or RNA from the sample, without considering the biological characteristics of the pathogen itself. Pathogen identification is achieved by analyzing its specific nucleic acid sequences. Detection techniques mainly include gene amplification, 16S rRNA, nucleic acid identification, and proteomics, all of which show great promise for rapid pathogen detection.
Automated blood culture systems and automated microbial identification and drug susceptibility testing systems are two major analytical systems in microbial testing. Automated blood culture systems are used to detect the presence of pathogens in samples; automated microbial identification and drug susceptibility testing systems can identify isolated pathogens and perform in vitro drug susceptibility tests. In addition, rapid microbial detection instruments using non-culture methods are widely used.
